Automatic control mechanism for fire trucks and the like



Aug. 20, 1929. A. HOLLANDER ET AL 1,725,273

AUTOMATIC CONTROL MECHANISM FOR FIRE TRUCKS AND THE LIKE Filed Oct. 19.

ilk,

gnuuni Patented Aug. 20, 1929.

UNITED STATES PATENT OFFICE.

ALADAR HOLLANDER, OF BERKELEY, AND W'ALTER L. FORWARD, OF OAKLAND, CALI- FORNIA, ASSIGNORS, BY MESNE ASSIGNMENTS, TO BYRON JACKSON PUMP 00., A

CORPORATION OF DELAWARE.

AUTOMATIC CONTROL MECHANISM FOR FIRE TRUCKS AND THE LIKE.

Application filed October 19, 1927. Serial No. 227,309.

Our invention has for its object means for controlling motor driven pump apparabus on a fire truck or the like, and includes automatic control as well as manual control during the operation of the pump under varying conditions of load.

Another object is an apparatus of the character described, adapted to control an internal combustion engine by shifting the fuel supply valve of said engine either by hand or automatic means, while retaining the automatic control most sensitive and accurate at all times.

Another object is in apparatus of the character described the removal of controlling springs from the said valve itself and incorporating the same in our controlling mechanism.

Centrifugal pumps to which our invention is particularly adapted have the characteristic that the same pressures may be obtained with them by changing their speed for different capacities.

It is often necessary on fire apparatus and other kinds of machines to often keep the pressure constant irrespective of the capacity, and irrespective of the load which the pump takes at that capacity; also, it is desirable to have this pressure, while constant for a certain point or a certain setting, vary in advance for different settings, or vary whenever a different pressure is required. Fut-hermore, on fire apparatus, a hand control limiting the range of automatic control is also desirable.

These result-s are attained by our invention in a very simple and satisfactory way, thru a compact mechanism and without interfering with other controls which, as in the case of an automobile fire engine are necessary when the engine is employed without the pump.

The whole automatic control may be cut out and only the hand control used, or both may be cut out, and either the conventional hand control and foot throttle used while operating the pump.

It is to be furthermore noted that but one control valve is required on the engine thereby eliminating any possible interference, either with proper carburation or proper throttling by interference of one valve with the other.

Other objects will appear from the drawings and specifications which follow.

In our apparatus we employ a diaphragm working on a piston, which piston is spring loaded, the spring being adjustable to suit the different pressures that have to be balanced and the piston (or in an alternate construction the cylinder) carrying the main support of the hand control and within that support the operating lever of the same hand control.

\Vith this arrangement the hand control may be operated at any time regardless of the position of the piston or the cylinder, and the automatic regulation is not cut out by the operation of this hand control. Furthermore, there are relatively large forces required to assure that the control valve follows the motion of either the hand or the automatic control, and the spring to insure this motion we arrange so that the tension is between the hand control quadrant support and the control lever. Thus the friction of the mechanism only has to be over come, ,while the spring tension will not change.

By referring to the drawing our invention will be made clear.

Fig. 1 is a diagrammatic showing of an automobile fire engine with our invention applied thereto.

Fig. 2 is a detail horizontal section through our controlling mechanism.

Fig. 3 is a detail vertical section through our control mechanism.

Fig. 4 is a different species of our invention wherein the cylinder is adapted to move and the axis of the hand control mechanism is retained fixed.

Throughout the figures similar numerals refer to identical parts.

An automobile fire engine is shown by the numeral 1, containing a centrifugal pump 2 adapted to be operated by the motor 3, the latter being under the hand control at 4 all in the conventional manner.

At 5 is shown an instrument board which is more conveniently located when the truck is parked and the centrifugal pump is being operated to supply a ump pressure to a plurality of fire hose 6, 8.

In apparatus of this character it is advisable that the operator have before him at the instrument board 5, means for hand controlling at any time the operation of the motor 4, and it is further imperative that should any of the hoses 6, 7, 8 be shut off or opened that the pump immediately and automatically respond to the reduced or increased water supply without a material variation in pressure thus if hose 6 is being dent.

To prevent this we employ automatic means to maintain the delivery pressure from the pump substantially constant under the varying demand of water quantity of the several hose streams 6, 7 8.

On the shaft 11 is mountedthe cam 19 against which bearsthe roller 20 carried on one end of an arm 21 fulcrummed at 22.

The roller 20 is kept tight against the cam 19 by the lever 23 fixed on the shaft 22 and held by the spring 24; adgustable by the thread and nut at 25 so that upon movement of the hand member 10 the arm 21 1S shifted through conventional connections 26 and the motor throttle 9 is operated to control the engine and therefore the pump.

Thus when the lever 10 is moved about the quadrant 13 the throttle valve 9 is opened or closed the requisite amount, thus effecting hand control of the motor 3 from the instrument board 5 and therefore hand control of the centrifugal pump 2.

The pressure from the centrifugal pump 2 is connected to the diaphragm inlet 14 and acts. as a force against the diaphragm l5 and piston 16 to compress the spring 17 against a force which may be adJusted by the nut and screw thread at 18.

The piston 16 moves within the cylinder 30 and has mounted upon it the bearing column 31 in which the shaft 11 is adapted to rotate.

The entire column 31 with the hand controlled member 10 is therefore shifted back and forth with the piston 16 within the cylinder 30 according to pressure variations transmitted from the pump through the pipe 14, and the movement of this piston causes the arm 21 to fulcrum about pin 22 and shift the connections 26 and throttle 9 to compensate for said pressure variations by changing the engine speed and thus maintains the pressure on the fire hose 6, 7 and 8 substantially constant, regardless of the amount of water delivered therethrough.

It will now be seen that the apparatus is automatically controlled at all times independent of the hand control 10 and that the hand control may be operated without at any time interfering with the automatic control.

They are mechanically tied together at all times although the operation of one does not preclude or interfere with the operation of the other.

Moreover, the hand control 10 may be set at any time so that the limit of operation of the pump will heany desired pump delivery, and the automatic control will function up to but not beyond said delivery; thus if'hose 6 be the only one employed the hand control 10 will be set to a position corresponding with one third pump capacity delivery, and the apparatus will automatically function to retain the pressure constant in the hose 6 regardless of whether a large or small stream be delivered therefrom.

If two hoses are employed the hand control 10 will be opened proportionally and the governor or automatic control will function throughout its range for the pump capacity.

If the third hose be connected the hand control 10 will be opened to the limit and the apparatus will automatically function to control the pressure up to the maximum delivery.

As an alternate form of our invention the piston 16 maybe fixed and the cylinder 30 may be allowed to move as shown in Fig. 4 thereby attaining the same results by substantially similar means while retaining the center of movement of the member 10 and shaft 11 fixed, without departure from the spirit of our invention.

The control of the motor throttle is extremely sensitive in our apparatus as it is only necessary to overcome the fraction of the several parts which are independent of the pressures exerted by the spring.

A most sensitive adjustment may therefore be attained while employing a balancing spring of high compression. 7

The spring is in effect an element entirely independent of the diaphragm movement.

lVe claim:

1. Controlling means 7 for motor driven centrifugal pumps comprising, a throttle for controlling said motor, a remote hand lever and actuating connections between said lever and said throttle including a cam and roller and a spring and means compelling the roller to follow said cam and an arm on which said roller is pivoted, a cylinder element and a piston element, a pipe from said pump dis charge to said cylinder, an adjustable spring opposing movement of said piston under said cylinder pressure, said hand lever fulcrummed to one of said elements and said arm fulcrummed to said other element.

2. Controlling means for motor driven cen- 1 trifugal pumps comprising, a throttle for controlling said motor, a remote hand lever and actuating connections between said lever and said throttle including a cam and a roller and a spring and means compelling the roller to follow said cam and an arm on which said roller is pivoted, a cylinder element and a piston element, a pipe from said pump discharge to said cylinder, an adjustable spring opposing movement of said piston under said cylinder pressure, a spindle having said hand lever fixed at one end thereof and said cam fixed at the other end thereof, a bearing fixed on said piston and carrying said spindle, a fulcrum mounted on said cylinder and supporting said arm.

3. In a control mechanism for fire trucks having motor driven pump apparatus, the combination of a throttle adapted to control the speed of said motor, a piston element and a cylinder element in which said piston is adapted to reciprocate and a duct communicating pressure from said pump to said cylinder, one of said elements fixed and the other of said elements adapted to operate mechanism which in turn actuates said throttle to vary the motor speed to maintain the pump discharge pressure constant, and spring adjusting means balancing the piston movement under the action of the said variable pump discharge, mechanism interposed between one of said elements and said throttle including manual means to adjust the range of said throttle movements.

4. In control mechanism for fire trucks having motor driven pump apparatus, the combination of a throttle adapted to control the speed of said motor, a piston element and a cylinder element in which said piston is adapted to reciprocate and a duct communicating pressure from said pump to said cylinder, one of said elements fixed and the other of said elements adapted to operate mechanism which in turn actuates said throttle to vary the motor speed to maintain the pump discharge pressure constant, and spring adjusting means balancing the piston movement under the action of the said variable pump discharge and a hand operable lever interposed in said mechanism constructed and adapted to independently vary the movement of said throttle and to adjust the range of movement of said throttle under the automatic action of said elements.

5. In control mechanism for fire trucks and the like having a motor driven pump, the combination of means controlling the power output of said motor, a hand lever and actuating connections between said lever and said control means including an arm, a spring and means compelling the movement of said arm including a cylinder element and a piston element, a pipe communicating fluid pressure from said pump to said cylinder, an adjustable spring opposing movement of said piston, said hand lever fulcrumed to one of said elements and said arm fulcrumed to said other element.

' ALADAR HOLLANDER. WALTER L. FORlVARD. 

